Harald Ossian Hjalmarson (14 July 1868 – 15 December 1919)[1] was a Swedish soldier who volunteered for the Finnish Civil War in 1918 on the white army.

It was an expression of burning resentment against the indifference of official Sweden, and even more so against the mighty hands, which put obstacles in the way of those who really wanted to help in a struggle that should have been everyone's, but became only a few.

Upon arriving in Vaasa, Hjalmarson was immediately recruited as a colonel in the Finnish White Army, and he was tasked with leading a 650-man special unit, which was to proceed through the red lines and go to help the embargoed Eastern Uusimaa protection municipalities.

However, the attempt failed, as the Uusimaa whites had already dispersed and Hjalmarson's men were beaten back in the Battle of Heinola at the end of February.

He won the Battle of Kuru on 15–17 March, but the siege of the Reds failed, as they withdrew from the front overnight and, unaware of the success of other army groups in Hjalmarson, did not embark on an effective pursuit.

[7] After the battle at Kuru, Hjalmarson's troops marched across the ice of Lake Näsijärvi from Teisko and went to help the Satakunta group commanded by Ernst Linder.

Despite his wishes, Hjalmarson did not get a permanent post in the Finnish army, as the Swedes were ousted from the German path as early as June 1918.